Tenant is not home to let in maintenance people

[Edward Norman]

Long story short: Tenant lets me know the dryer isn't functioning properly. The dryer is still under warranty so I call the company and schedule for someone to come take a look. I immediately let the tenant know the date and time window and she says that works. The day of the repair company calls me and says the tenant isn't home and they can only wait 5 more minutes. I call the tenant and she calls her mother who lives  near by to have them head over, but by this time its too late. At this point now I have to call the maintenance people and schedule it again (hopefully I wont be charged) 

How do you all deal with issues like this, or prevent them?